Urban fossils of Brussels

Most of the buildings of downtown Brussels have been built with artificial materials such as bricks and concrete. Natural construction stones are not very common around this city, therefore using artificial construction materials is quite common in the region. However, some streets and squares of Brussels have been paved with a dark limestone (see photograph below) with a very rich and interesting fossil content.

This limestone has also been used to clad some important buildings of Brussels. However, these stones have not been polished, so fossils are not easily recognised.

Limestone slabs used as paving stones are well polished, specially in pedestrian streets, where the combination of abundant rain and thousands of daily steps has created smooth surfaces. Fossils are very clearly seen on this polished surfaces, creating a distinctive contrast with the dark matrix.

If you look at the surface of this limestone in detail, it preserves small fossil fragments. Sometimes, these fragments are the main element, so the whole rock is actually an aggregate of fossils. However, these fossils are often embedded in a dark, fine grained matrix of carbonate.

The most common fossil groups preserved in this limestone are corals and crinoids. The largest fossils are usually coral colonies; some of these colonies preserve the internal structure that individual corallites can actually be recognised. Crinoid fossils are represented by tiny fragments of their stems and arms, made of calcareous ossicles.

Brachiopod fossils are also relatively common in these paving stones. These fossils are usually fragmented and their shape depends on the orientation of the shell relatively to the stone surface.

There is another site for urban fossil lovers in Brussels: Le Grand Café, in the city center. The floor of this cafeteria is paved with a brown limestone that preserves beautiful fossils. The most impressive remains of ancient life are ammonites, some of them several centimetres in diameter.